small cleanup for diff-delta.c

This patch removes unused remnants of the original xdiff source.
No functional change.  Possible tiny speed improvement.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/diff-delta.c b/diff-delta.c
index b2ae7b5..890986e 100644 (file)
--- a/diff-delta.c
+++ b/diff-delta.c
@@ -84,20 +84,15 @@ typedef struct s_chanode {
 } chanode_t;
 
 typedef struct s_chastore {
-       chanode_t *head, *tail;
        int isize, nsize;
        chanode_t *ancur;
-       chanode_t *sncur;
-       int scurr;
 } chastore_t;
 
 static void cha_init(chastore_t *cha, int isize, int icount)
 {
-       cha->head = cha->tail = NULL;
        cha->isize = isize;
        cha->nsize = icount * isize;
-       cha->ancur = cha->sncur = NULL;
-       cha->scurr = 0;
+       cha->ancur = NULL;
 }
 
 static void *cha_alloc(chastore_t *cha)
@@ -111,12 +106,7 @@ static void *cha_alloc(chastore_t *cha)
                if (!ancur)
                        return NULL;
                ancur->icurr = 0;
-               ancur->next = NULL;
-               if (cha->tail)
-                       cha->tail->next = ancur;
-               if (!cha->head)
-                       cha->head = ancur;
-               cha->tail = ancur;
+               ancur->next = cha->ancur;
                cha->ancur = ancur;
        }
 
@@ -127,7 +117,7 @@ static void *cha_alloc(chastore_t *cha)
 
 static void cha_free(chastore_t *cha)
 {
-       chanode_t *cur = cha->head;
+       chanode_t *cur = cha->ancur;
        while (cur) {
                chanode_t *tmp = cur;
                cur = cur->next;
@@ -142,7 +132,6 @@ typedef struct s_bdrecord {
 } bdrecord_t;
 
 typedef struct s_bdfile {
-       const unsigned char *data, *top;
        chastore_t cha;
        unsigned int fphbits;
        bdrecord_t **fphash;
@@ -152,7 +141,7 @@ static int delta_prepare(const unsigned char *buf, int bufsize, bdfile_t *bdf)
 {
        unsigned int fphbits;
        int i, hsize;
-       const unsigned char *base, *data, *top;
+       const unsigned char *data, *top;
        bdrecord_t *brec;
        bdrecord_t **fphash;
 
@@ -165,13 +154,12 @@ static int delta_prepare(const unsigned char *buf, int bufsize, bdfile_t *bdf)
                fphash[i] = NULL;
        cha_init(&bdf->cha, sizeof(bdrecord_t), hsize / 4 + 1);
 
-       bdf->data = data = base = buf;
-       bdf->top = top = buf + bufsize;
-       data += (bufsize / BLK_SIZE) * BLK_SIZE;
+       top = buf + bufsize;
+       data = buf + (bufsize / BLK_SIZE) * BLK_SIZE;
        if (data == top)
                data -= BLK_SIZE;
 
-       for ( ; data >= base; data -= BLK_SIZE) {
+       for ( ; data >= buf; data -= BLK_SIZE) {
                brec = cha_alloc(&bdf->cha);
                if (!brec) {
                        cha_free(&bdf->cha);
@@ -208,7 +196,7 @@ void *diff_delta(void *from_buf, unsigned long from_size,
 {
        int i, outpos, outsize, inscnt, csize, msize, moff;
        unsigned int fp;
-       const unsigned char *data, *top, *ptr1, *ptr2;
+       const unsigned char *ref_data, *ref_top, *data, *top, *ptr1, *ptr2;
        unsigned char *out, *orig;
        bdrecord_t *brec;
        bdfile_t bdf;
@@ -224,6 +212,8 @@ void *diff_delta(void *from_buf, unsigned long from_size,
                return NULL;
        }
 
+       ref_data = from_buf;
+       ref_top = from_buf + from_size;
        data = to_buf;
        top = to_buf + to_size;
 
@@ -253,7 +243,7 @@ void *diff_delta(void *from_buf, unsigned long from_size,
                i = HASH(fp, bdf.fphbits);
                for (brec = bdf.fphash[i]; brec; brec = brec->next) {
                        if (brec->fp == fp) {
-                               csize = bdf.top - brec->ptr;
+                               csize = ref_top - brec->ptr;
                                if (csize > top - data)
                                        csize = top - data;
                                for (ptr1 = brec->ptr, ptr2 = data; 
@@ -262,7 +252,7 @@ void *diff_delta(void *from_buf, unsigned long from_size,
 
                                csize = ptr1 - brec->ptr;
                                if (csize > msize) {
-                                       moff = brec->ptr - bdf.data;
+                                       moff = brec->ptr - ref_data;
                                        msize = csize;
                                        if (msize >= 0x10000) {
                                                msize = 0x10000;